The program involves studies of aging and senescence at the cellular level. Spanning of amoebae and of mammalian diploid cells will be studied particularly by cell reassembly from components, by cell fusion, by observation of RNA and protein synthesis, and by the isolation and identification of control factors involved in cell senescence. Concomitant theoretical studies will be made of the basic aspects of cell senescence, and of the possible relevance of e.g., complex oscillators, error accumulation, gene transport by viruses, in cell senescence.